Professor Andy Radford, a Behavioural Biologist at the University of Bristol describes how the Pied Babbler uses the Watchman's song in its role as a sentry whilst the rest of the flock forage for food on the ground. Tweet of the Day has captivated the Radio 4 audience with its daily 90 seconds of birdsong. But what of the listener to this avian chorus? In this new series of Tweet of the Day, we bring to the airwaves the conversational voices of those who listen to and are inspired by birds. Building on the previous series, a more informal approach to learning alongside a renewed emphasis on encounter with nature and reflection in our relationship with the natural world. Producer: Sarah Blunt Photograph: Petrus van Zyl.